1. Field of the Invention
The present invention relates to a so-called surface conduction electron emitting device, for causing electron emission by supplying a current to a coarse resistor film, and a process for producing the same.
2. Related Background Art
A surface conduction electron emitting device is provided with a coarse resistor film in which the film-constituting material is discontinuous as an island structure or has defects, and emits electrons by supplying a current to such resistor film.
Conventionally such coarse resistor film has been obtained by forming, on a insulating substrate, a thin film of metal, metal oxide or semi-metal by chemical vapor deposition or sputtering, and applying a current to thus formed film of several ohms to several hundred ohms to cause local destructions of the film by Joule's heat, thereby obtaining a resistance of several killoohms to several hundred megaohms.
However, because of such forming process, the electron-emitting device cannot be formed on another semiconductor device but has to be formed as a separate device. The manufacturing process is therefore inevitably complex, and it has been difficult to achieve compactization through integration with a driving circuit.
Besides, in the conventional coarse resistor film utilizing metal, metal oxide or semi-metal, the quantity of electron emission is increased by forming, on the surface of said film, a layer of a material for reducing the work function such as a Cs or CsO layer, stable electron emission cannot be expected since the alkali metal such as cesium is unstable.
Such unstability can be prevented by forming a silicide of such alkali metal, but the formation of a silicide or oxide layer on the conventional thin film of metal, metal oxide or semi-metal complicates the manufacturing process.
Also such conventional forming process is unstable, so that the produced electron emitting devices show fluctuation in the efficiency of electron emission and are associated with a short service life.